Sanding device

ABSTRACT

A PAIR OF FRAME SECTIONS WITH WIDE FLAT RIMS ARE ADJUSTABLY CONNECTED TO EACH OTHER TO FORM A FRAME ASSEMBLY OF ADJUSTABLE LENGTH. RESILIENT PADDING IS SECURED TO ONE SIDE OF THE FRAME ASSEMBLY (ALSO REFERRED TO HEREIN AS A FRAME) AND A SHEET OF ABRASIVE MATERIAL IS SECURED THERETO BY ADJUSTMENT OF THE FRAME SECTIONS APART FROM EACH OTHER. THE ABRASIVE MATERIAL MAY BE A CONTINUOUS BELT ALL THE WAY AROUND THE FRAME, OR IT MAY BE A STRIP WHOSE ENDS ARE SECURED IN BARBED SLOTS AT THE OUTER ENDS OF THE FRAME. THE ILLUSTRATED FRAME IS ABOUT TWO INCHES WIDE AND DEEP, HAVING A TOP ABOUT FOUR INCHES LONG AND A BOTTOM ABOUT SIX INCHES LONG IN A TARPEZOIDAL SHAPE WITH POINTED LOWER ENDS. SLIDE PINS AND A SCREW ARE USED FOR COUPLING THE FRAME SECTIONS AND FORCING THEM APART TO SECURE THE ABRASIVE MATERIAL IN PLACE.

Feb. 16, 1971 P. A. ERIKSEN 3,562,967

SANDING DEVICE 2 Sheets$heet 1 Filed Jan. 28, 1969 Feb. 16, 1971 I P. A. ERIKSEN 3,562,967

SANDING DEVICE Filed Jan. 28, 1969 2 Sheets-Sheet 2 United States Patent 3,562,967 SANDING DEVICE Paul A. Eriksen, Cleveland Ave., McDaniel Heights, Wilmington, Del. 19803 Filed Jan. 28, 1969, Ser. No. 794,725 Int. Cl. B24d /00 US. Cl. 51--372 18 Claims ABSTRACT OF THE DISCLOSURE A pair of frame sections with wide flat rims are adjustably connected to each other to form a frame assembly of adjustable length. Resilient padding is secured to one side of the frame assembly (also referred to herein as a frame) and a sheet of abrasive material is secured thereto by adjustment of the frame sections apart from each other. The abrasive material may be a continuous belt all the way around the frame, or it may be a strip whose ends are secured in barbed slots at the outer ends of the frame. The illustrated frame is about two inches wide and deep, having a top about four inches long and a bottom about six inches long in a trapezoidal shape with pointed lower ends. Slide pins and a screw are used for coupling the frame sections and forcing them apart to secure the abrasive material in place.

BACKGROUND OF THE INVENTION Various block devices have been proposed for mounting and applying sheets of sandpaper and other abrasivematerials to work surfaces. Examples of such devices are described in the following US. Pats: 2,400,928, 2,457,- 466, 2,493,852, 2,531,588, 2,761,257, 3,063,208, 3,106,806. All of such known devices have the disadvantage of being essentially blocks with shallow indentations or depressions for receiving the tips of the users fingers. This makes them somewhat diflicult to manipulate. Most of them can only be used with endless abrasive belts and with the exception of Pat. 2,400,928 cannot utilize strips of sandpaper. An object of this invention is to provide a simple and economical sanding device which is highly efficient in manipulation and operation. Another object is to provide such a device which can be used with strips as well as belts of abrasive sheet material.

SUMMARY OF THE INVENTION A sanding device employing belts or strips of abrasive material comprises a frame assembly adapted for comfortable and efficient manipulation. It includes a pair of frame sections with laterally extended rims, which support the abrasive material. These frame sections are coupled by a diverging means which adjusts them away from each other to secure the abrasive material in place. The rims and open sections within them are respectively thin and ample with smooth corners to permit the hand of a user to comfortably grasp and manipulate the device with the fingers wrapping into the open sections. Particularly effective forms are provided by a substantially quadrilateral frame and more particularly by a trapezoidal frame. The coupling device may include a pin and screw with a wide knob and re-entrant barbed slots are particularly effective for securing strips of abrasive to one side of the frame.

BRIEF DESCRIPTION OF THE DRAWINGS Novel features and advantages of the present invention will become apparent to one skilled in the art from a reading of the following description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which:

FIG. 1 is a side view in elevation partially broken away in cross section of one embodiment of this invention; FI21G. 2 is a top plan view of the embodiment shown in FIG. 3 is an end view of the embodiment shown in FIGS. 1 and 2;

FIG. 4 is an enlarged cross sectional view of a portion of the embodiment shown in FIG. 1;

FIG. 5 is a side view in elevation partially broken away in cross section of another embodiment of this invention;

FIG. 6 is a top plan view of the embodiment shown in FIG. 5;

FIG. 7 is an end view of the embodiment shown in FIG. 5; and

FIG. 8 is a cross sectional view taken through FIG. 5 along the line 8-8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. l-4 is shown sanding device or frame assembly 10 including a pair of frame sections 12 and 14. Frame sections 12 and 14 are connected together and diverged from each other by coupling means 16 including pins 18 and diverging means 19 including screw 20. Pins 18 are secured to right-hand frame section 14 by any convenient means such as molding or die casting within it. Frame sections 12 and 14 are conveniently molded into shape out of relatively strong, shockproof and readily available, inexpensive materials such as die-casting metals or plastics such as: ABS, phenolics, polystyrene, etc.

Pins 18 are inserted to slide within corresponding holes 22 in left-hand frame section 12 as shown in FIG. 1. Stop lug 24 within keyhole slot 26 abuts upon removable plate 30 to prevent sections 12 and 14 from coming apart. Screw 20 is threaded within inner side 32 of left-hand section 12 within hole 34. Helical spring thread 36 is molded within the periphery of hole 34 to retain screw 20. Screw 20 also includes a large knurled head 38 to facilitate adjustment. The inner end 40 of screw 20 bears against metal wear plate 42 molded within inner side 44 of frame section 14. Manipulation of screw 20 therefore adjusts the overall length of frame assembly 10 for reasons later discussed in detail.

Frame sections 12 and 14 have laterally extended rims 46 and 48 for supporting pads and belts of the abrasive material, such as strip 50 of sandpaper or an endless belt 52 of sandpaper shown in phantom outline in FIG. 1. Movement of screw 20 toward right-hand plate section 14 causes the sections to diverge and lengthens frame as sembly 10. This firmly secures strip 50 or belt 52 to frame 10 as later described in detail.

Pad 54 of relatively soft resilient material such as polyurethane foam is secured to the bottom rims 46 and 48 of sections 12 and 14 to provide a cushion under sandpaper strip 50 and the adjacent portion of belt 52. Belt 52 is mounted on frame 10 by shortening it. This is accomplished by withdrawing screw 20 and pushing the sections together by hand. Belt 52 can then be loosely applied around frame 10 after which insertion of screw 20 toward frame section 14 lengthens assembly 10 in firm contact within belt 52.

Strip 50 is alternatively secured against pads 54 by insertion of one end 56 within re-entrant slot 58 in the pointed lower end 60 of sections 12 and 14. The bases 61 of slots 58 extend toward pads 54 to form an angular entrance 62 at which barbs or points 64 are disposed. Barbs 64 impale ends 56 of strips 50 when they are inserted into slots 58. Screw 20 is then manipulated to push sections 12 and 14 part. Barbs 64 in conjunction with reversely bent ends 56 firmly secure strip 50 in contact with pads 54 on the bottom side of frame 10.

Enlarged FIG. 4 shows how barbs 64 are disposed with reference to slots 58. Barbs 64 are formed upon the outer ends of pins 66 which are secured within slot entrance section 62, for example, 'by molding within them. Pins 66 are effectively made of steel and have the outer ends 68 chamfered to lie within the outer surfaces of rims 46 and 48. This maintains them out of contact and prevents them from interfering with a belt 52. Points or barbs 64 may also be formed as serrations of the same material of which sections 12 and 14 are molded and they remarkably optimize retention of strips 50 in slots 58. This retention is highly effective even though slots 58 are much wider than strips 50 and are tapered inwardly from entrance to base 61 to facilitate insertion. The positive divergence of frame 14 by means of screw 20 also facilitates mounting strip 50, its impalement on barbs 64 and retention within slots 58.

Laterally extended rims 46 and 48 enclose openings 72 and 74 within sections 12 and 14. These openings permit the hand of a user (not shown) to comfortably grasp frame 10 with fingers wrapping into and through openings 72 and 74. Frame 10 is conveniently grasped at upper ribs 46 and 48 with the fingers coiling through openings 72 and 74. This mode of handling is facilitated by the thin tapered cross section 76a of rims 46a and 48a shown in FIG. 8. FIG. 8 is representative of another embodiment of this invention, but cross section 76a is the same for both embodiments. As shown in FIG. 8, all edges 78a and 80a of rims 46a and 48a are smoothed to provide maximum comfort and efficiency for grasping and manipulation. Bosses 82a provide sufficient space for receiving pins 18a and screw 20a.

Sections 12 and 14, as shown in FIG. 1, are substantially quadri-lateral to impart a trapezoidal shape to overall frame assembly 10. A highly effective shape and size for frame 10 is shown in the drawings as for example about two inches wide and deep with a top about four inches long and a bottom about six inches long. The pointed lower ends of the trapezoidal form facilitate entry into restricted spaces. This is enhanced by the tapered ends 84 of pads 54. The aforementioned shape and approximate size of frame 10 gives it the overall appearance and feel of a plane instead of a block to make this sanding device completely different in kind from the pre-existing block type of sanding device. It makes it possible for the user to employ his entire hand and fiingers in a comfortable and efficient grasp instead of the restriction of previous devices to tips of the fingers and palms. This grasping and manipulating facility is further enhanced by the sloped end rims extending downwardly from the shorter upper rims. This permits the fingers to conveniently overlap the front and rear of frame 10 to guide its movement. The aforementioned smooth edges within and about the peripheries of openings 72 and 74 further facilitate manipulation of device 10. The disposition of the wide knob 38 or screw 20 within opening 72 further facilitates manipulation and adjustment of frame 10.

In FIGS. -8 is shown frame a which is similar in all respects to frame 10 with the exception of employing a pair of retaining plates 86a to hold strips 50a and 88a instead of barbed slots. Plates 86a are received within stepped recesses 90a in outer sides of rims 46a and 48a with projecting ends 92a extending inwardly into grooves 94a in recesses 90a. Projections 92, which are conveniently bent from the ends of plates 86a, secure ends 56a of sandpaper strips 50a and 88a to grooves 94a when knurled nuts 96a are screwed down onto threaded steps 87a attached to the inside of plates 86a. This permits strips 50a and 88a of sandpaper to be attached to both the upper and lower surfaces of frame 10a to provide different reactions against different work materials. Strip 50a is given a softer reaction by pads 54a and strip 88a is given a stiffer and harder reaction because of its contact with harder upper surface of frame 10a. Strips 50a and 88a may be used simultaneously or separately. During simultaneous application, nuts 96a may only be slightly tightened until divergence of frame sections 12a and 14a equalizes the retained lengths. Then nuts 96a are fully tightened to firmly secure strips 50a and 88a in place. Previously mentioned belt 52a may also be utilized about frame 10a with plates 86a drawn down out of the way within recesses a.

I claim:

1. A sanding device employing belts or strips of abrasive sheet material comprising a pair of frame sections having laterally extended rims, coupling means connecting inner ends of said frame sections to each other with adjacent sides of said rims substantially aligned to form an elongated frame assembly of adjustable length, said rims surrounding substantial openings, the outer surfaces of said rims being substantially flat for supporting a sheet of abrasive material, diverging means reacting between said frame sections for adjusting said frame sections away from each other whereby said abrasive sheet material is firmly contacted to said rims, said rims being thin, said openings being ample, and all corners thereof being smooth to permit a user to comfortably and efficiently manipulate said frame with fingers wrapping into said openings.

2. A sanding device as set forth in claim 1 wherein said frame sections are substantially quadrilateral.

3. A sanding device as set forth in claim 2 wherein at least one of said frame sections has an acute angular end to facilitate entry into restricted space.

4. A sanding device as set forth in claim 3 wherein both of said frame sections have acute angular ends.

5. A sanding device as set forth in claim 4 wherein said frame assembly is trapezoidal.

6. A sanding device as set forth in claim 1 wherein said coupling and diverging means respectively comprise slide pin means movably connecting said inner ends of said frame sections to each other and screw means mounted within one of said inner ends and reacting against the other to force said frame sections apart.

7. A sanding device as set forth in claim 6 wherein said slide pin means comprises a pair of pins with said screw means disposed between them.

8. A sanding device as set forth in claim 7 wherein elongated bosses are disposed within said frame sections for receiving said slide pin and screw means.

9. A sanding device as set forth in claim 6 wherein said screw means has a wide knob disposed in one of said openings to facilitate adjustment thereof.

10. A sanding device as set forth in claim 1 wherein said rims taper laterally to relatively thin outer edges.

11. A sanding device as set forth in claim 1 wherein reentrant slot means is disposed at the outer ends of said frame assembly for receiving the ends of a strip of said abrasive sheet material, and barbed means are disposed at the entrance to said slotted means whereby said strips are impaled to secure them to said frame assembly when said diverging means is operated to adjust said frame sections apart, and said barbed means being substantially disposed within the outer surface of said rims to prevent them from interfering with a belt of said abrasive sheet material mounted about said rims.

12. A sanding device as set forth in claim 1 wherein at least one end of said frame assembly is angularly pointed to facilitate access into restricted space and a pad of substantially soft resilient material is disposed on the side of said frame assembly adjacent said pointed end.

13. A sanding device as set forth in claim 12 wherein both of said ends are angularly pointed to make said frame assembly substantially trapezoidal with one side longer than the other.

14. A sanding device as set forth in claim 13 wherein said re-entrant slot means extends into said angularly pointed ends.

15. A sanding device as set forth in claim 14 wherein the base of said re-entrant slot means is directed towards said longer side of said frame assembly.

16. A sanding device as set forth in claim 15 :wherein said re-entrant slot means is tapered outwardly toward its entrance to facilitate insertion of the ends of said strips within it.

17. A sanding device as set forth in claim 1 wherein strip retaining plates are mounted in the outer ends of said frame sections, and adjustable securing means connect said plates to said outer ends for attaching the ends of a strip of said abrasive sheet material thereto.

18. A sanding device as set forth in claim 13 wherein recesses are disposed in said outer ends for receiving said References Cited UNITED STATES PATENTS 1,893,679 l/1933 Quinn 5l372X 2,400,928 5/1946 Hein 51--372 3,063,208 11/1962 Bell et a1. 51-391X OTHELL M. SIMPSON, Primary Examiner US. Cl. XR. 51392 

